Urinary infection and chronic renal disease in pregnancy

[em]Urinary infection. Minor urinary symptoms (frequency and stress or urge incontinence) are common in pregnancy. Cystitis (bladder infection) is not more common during pregnancy than it it is at other times, but because the ureters dilate during pregnancy, infection is more likely to spread proximally and cause acute pyelonephritis.

One pregnant woman in 20 has an asymptomatic bacteriuria, but because you can only diagnose this by routine screening, it will not be a problem you notice. A quarter of patients with bacteriuria have an acute attack of pyelonephritis, which affects 1[nd]2 per cent of pregnant women. Bacteriuria is associated with an increased risk of prematurity, but there is no evidence that treatment reduces this risk. Treatment does however reduce the risk of pyelonephritis, so it is worth doing.

Chronic renal disease is not adversely affected by pregnancy unless a patient is already in renal failure, or has pyelonephritis. Advise her as described below. Chronic renal disease can also cause severe hypertension (17.4).[+3]

URINARY DISEASE IN PREGNANCY URINARY INFECTION can usually be treated without difficulty. If you cannot culture a patient's urine, use ''[mt]10 white cells in one high-power microscope field' as evidence of infection.

If she has no symptoms and you find bacteria on screening, only treat her if she has [mt]100,000 bacteria/ml.

If she has symptoms suggestive of cystitis (dysuria and frequency), manage her like this:

If you can examine her urine, treat her if you find any bacteria in her urine.

If you cannot examine her urine and she does not have the symptoms of pyelitis (see below), her symptoms may be due to: (1) Bacterial cystitis. (2) Schistosomiasis (in endemic areas). (3) Pressure of her pregnant uterus on her bladder. (4) Vaginitis.

Exclude vaginitis by examining her with a speculum. Meanwhile, try sulphadimidine 500 mg three times a day for a week. This small dose is often effective, and will not harm the fetus. Nitrofurantoin in therapeutic doses (100 mg 6-hourly) often causes nausea, and is less suitable. Or give her ampicillin, if you can spare it for such a comparatively minor problem.

If she has fever, rigors, frequency dysuria, and loin tenderness, she has pyelonephritis. Admit her, and give her a broad-spectrum antibiotic (2.8), such as chloramphenicol, ampicillin, trimethoprim, or gentamicin, intravenously if possible for the first 12 hours, and continued orally for at least a week and preferably longer. When she has recovered, give her a prophylactic antibiotic, such as a low dose of nitrofurantoin (100 mg daily) until delivery.

CAUTION ! If a pregnant mother has a fever without any obvious symptoms (a ''PUO'), the causes include malaria, typhoid, miliary tuberculosis, and infection of her urinary tract. Culture her urine, and if possible her blood.

CHRONIC RENAL DISEASE during pregnancy (uncommon).

If her blood urea (normal in pregnancy [lt]6 mmol/l), or her creatinine ([lt]100 [gm]mol/l) are normal or nearly so, her prognosis is good.

If her blood urea is 6[nd]10 mmol/l or her creatinine is 100[nd]250 [gm]mol/l, she is likely to have a hectic pregnancy complicated by severe hypertension, and perhaps by progressive renal failure, which will probably require early delivery. Risks to her and her baby are increased. At the upper limit of this range she is at risk from DIC. Some obstetricians advise against pregnancy at creatinine levels [mt]180 [gm]mol/l.

If her urea is [mt]10 mmol/l or her creatinine is [mt]250 [gm]mol/l, the outlook for a successful pregnancy without dialysis or transplantation is very poor, so advise termination strongly.

If she has an attack of acute renal failure on top of chronic renal failure, she is unlikely to recover.